Re: [PATCHSET cgroup/for-3.8] netcls_cgroup: implement hierarchy support

[Daniel Wagner <daniel.wagner-98C5kh4wR6ohFhg+JK9F0w@public.gmane.org>]

Hi Tejun,

On 17.11.2012 04:30, Tejun Heo wrote:
> Hello, guys.
> 
> This patchset implements proper hierarchy support for netcls_cgroup.
> Pretty simliar to the netprio one[3].  Simpler as each cgroup has
> single config value instead of array of them.
> 
> This patchset contains the following three patches.
> 
>   0001-netcls_cgroup-introduce-netcls_mutex.patch
>   0002-netcls_cgroup-introduce-cgroup_cls_state-is_local.patch
>   0003-netcls_cgroup-implement-proper-hierarchy-support.patch
> 
> This patchset is on top of
> 
> cgroup/for-3.8 ef9fe980c6 ("cgroup_freezer: implement proper hierarchy support")
> + [1] "[PATCHSET cgroup/for-3.8] cgroup: allow ->post_create() to fail"
> + [2] "[PATCH 1/2] cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/"
>        "[PATCH 2/2] cgroup, cpuset: remove cgroup_subsys->post_clone()"
> + [3] "[PATCHSET cgroup/for-3.8] netprio_cgroup: implement hierarchy support"
> 
> and available in the following git branch.
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-netcls_cgroup-hierarchy
> 
> diffstat follows.
> 
>   include/net/cls_cgroup.h |    1
>   net/sched/cls_cgroup.c   |  102 ++++++++++++++++++++++++++++++++++++++++-------
>   2 files changed, 88 insertions(+), 15 deletions(-)
> 
> Thanks.

I played a bit around with this series, e.g. creating a hierarchy and and changing 
the root classid and seeing the change propagating through the hierarchy. Everything
worked as described in the documentation.

Sorry to bring this up again: how should to root cgroup behave? If the ultimate
goal to have only one single hierarchy then I would assume it is important that
the semantic for all controllers are the same. As you pointed out the networking
controllers are kind of a strange beast in the zoo of the cgroup controllers. 
But still I would assume that all root controllers behave the same. memcg or cpu*
are not expected to do any work in the root cgroup.

cheers,
daniel